1. Field of the Invention:
The present invention relates to a pyrotechnic charge structure, in particular for use as propellant in a rocket motor, which charge structure has a predetermined longitudinal extension and transversal cross sectional area adapted to the intended purpose.
2. Description of Background Art:
In some types of weapons for various uses, it is particularly important that the propellant for a projectile is burnt extremely fast, i.e. within 5-10 milliseconds. Typical examples are shoulder launched weapons like M-72, Carl Gustav, or weapons where the marksman is standing adjacent to the weapon. Such weapons are not allowed to have extensive tail-off, i.e. they need to burn out instantly without prolonged burning time to decrease gas pressure. In shoulder fired weapons the projectile is shot out from a launcher. Here it will be of most importance that the propellant is burnt out before the projectile leaves the launcher. If not, the combustion gases, and possibly flashes and residual products from the combustion will be thrown toward the face and body of the marksman and cause severe injuries.
According to the present invention is a pyrotechnic charge structure of the introductorily described type provided, which is distinguished in that the pyrotechnic charge structure, in transversal cross section, is in cellular form aimed at having similar wall thickness for all the cells in the charge structure, and in which the wall of the cells comprises the pyrotechnic charge, i.e. the propellant, and each cavity of the cells occupies air or oxygen-rich gas.
The advantage with this pyrotechnic charge structure is as follows. Subsequent to the ignition of the propellant it will be burning from all of the surfaces simultaneously and perpendicular to the surfaces of the cell walls, or webs, until it all is simultaneously burnt out. This may happen extremely fast since the thickness of the cell walls is at a minimum at the same time as the said thickness is substantially the same all around the cell. In addition is a high burning pressure generated (rapidly up and rapidly down). Such a propellant is a high-energy fuel that can be utilized in an effective way for launching missiles/rockets.
In a preferable embodiment the cells are in the form of a polygonal structure. In one for the time being particularly preferred embodiment, the cells have the form of a honeycomb structure. Other conceivable embodiments of the cell structure are a lattice structure, for example having square cellular form, a triangle structure, a circle structure and an oval structure.
Advantageously the charge can be a fuel of the composite type, like HTPB (Hydroxyl Terminated Polybutadiene), HTPE (Hydroxyl Terminated Polyether), CTPB (Carboxyl Terminated Polybutadiene), or molded double base or other moldable powder/propellant types and combinations.
According to the size of the weapon, the wall thickness of the cells will be adapted to the actual dimensions, and the wall thickness of the cells will typically be in order of magnitude 1-5 mm.
Other and further objects, features and advantages will appear from the following description of for the time being preferred embodiments of the invention, which are given for the purpose of description, without thereby being limiting, and given in context with the appended drawings where:
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.